(See "Single-Dose Pharmacokinetics of F in Epileptic Patients" report.) Based on the fitted parameters obtained from the single dose studies, the steady-state F levels were predicted at 1 hr post-drug administrtion (100 mg, P.O., t.i.d.). Comparison of the predicted plasma F level at 1 hr (1.28 mg/liter) correspondended reasonably well with the observed plasma F level at two different stages of the study in one patient (one week at steady-state: 1.4222 mg/liter and two weeks at steady-state: 1.423 mg/litter). At this juncture, the data appear to suggest that multiple dosing with F does not cause either inhibition, saturation or induction of the metabolic enzyme system. However, the data from all patients will have to be evaluated to further substantiate this observation. The observed steady-state plasma F levels and their comparison with those predicted from single dose studies will help in establishing if the linear pharmacokinetics are obeyed with F.